This invention relates to fibrous slivers having particulate matter distributed therethrough and, particularly, to absorbent bodies made from such slivers and used in such body fluid absorbent products such as catamenial tampons and napkins, diapers, surgical sponges, wound dressings, and the like.
Products of this type are generally made from carded slivers of such fibrous material as cellulosic fibers; e.g., cotton or regenerated cellulosic fibers i.e., rayon, either in their natural chemical state, or more recently, in a chemically modified state which renders the fibers more absorbent. There are currently, on the market, body fluid absorbent products which contain, in addition to cellulosic fibrous absorbents, certain hydrophillic particulate materials which have been variously termed "super absorbents" or "hydrocolloids" and share the common characteristics of being highly absorbent and swellable and, hence, will greatly increase the absorbent capacity of these body fluid absorbing products. Additionally, it is sometimes desirable to include other particulate matter into absorbent bodies, such as, for example, deodorants and anti-microbial agents.
In general, these added particulate materials best perform their desired functions when they are dispersed as homogeneously as is possible within the absorbent body. When this is accomplished, the absorbent body will exhibit uniform physical properties and the likelihood for the particulate matter to dust out during the manufacturing and packaging process, during handling when storing or shipping, or in use will be minimized.
Unfortunately, it has heretofore been difficult to produce absorbent bodies comprising a sliver of fibrous absorbent material having, homogeneously distributed therethrough, particulate matter, in a manner commensurate with high speed manufacturing processes. This problem is acknowledged in U.S. Pat. No. 4,105,033 wherein the use of grafted cellulose powder in such products as catamenial tampons is described.
As is suggested in this patent, a simple method of distributing such powder is to merely sprinkle the powder onto the surface of a rectangular sliver of fibers and then to fold or roll the sliver into the desired shape of the absorbent body. While this solution no doubt offers the advantage of processing simplicity, the resulting product is far from the ideal of homogenous distribution and, instead, produces a product having alternating strata of fibrous web and particulate matter. The drawback of this construction is manifested in tampons, for example, by decreased absorbent capacity, increased "sloughing", i.e., the release of particulate matter from the tampon during handling and use, and increased "telescoping" i.e., the unraveling of the finished tampon after use.
Accordingly, there is a need for producing a sliver of relatively long fibrous material and relatively small particulate matter wherein the particulate matter is well distributed throughout the fibrous sliver.